20861406518400 has 1152 divisors, whose sum is σ = 87197861836800. Its totient is φ = 4649563054080.

The previous prime is 20861406518363. The next prime is 20861406518423. The reversal of 20861406518400 is 481560416802.

It is a happy number.

20861406518400 is a `hidden beast` number, since 2 + 0 + 8 + 61 + 406 + 5 + 184 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 6232865527 + ... + 6232868873.

It is an arithmetic number, because the mean of its divisors is an integer number (75692588400).

Almost surely, 2^{20861406518400} is an apocalyptic number.

20861406518400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20861406518400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43598930918400).

20861406518400 is an abundant number, since it is smaller than the sum of its proper divisors (66336455318400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20861406518400 is a wasteful number, since it uses less digits than its factorization.

20861406518400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4146 (or 4126 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The spelling of 20861406518400 in words is "twenty trillion, eight hundred sixty-one billion, four hundred six million, five hundred eighteen thousand, four hundred".